Accumulation of tetracycline was hazardous to human health and ecosystems. Ag2ZnGeO4/g-C3N4 heterojunction photocatalysts were successfully prepared by the wet impregnation method. The morphological structure and optical properties of the photocatalysts were measured by a series of characterization methods. Moreover, Ag2ZnGeO4/g-C3N4 with a loading ratio of 20 % exhibited excellent photocatalytic activity by exploring the Ag2ZnGeO4 loading, catalyst dosage, initial concentration, and initial pH of tetracycline. The degradation efficiency of 20 % Ag2ZnGeO4/g-C3N4 for 10 mg/L TC was 94.29 % at 0.2 g/L catalyst dosage, and the corresponding first-order reaction rate constant reached a maximum of 0.0199 min−1. In addition, according to the results of the trapping experiments, superoxide anion radical was the major active species. Eventually, a possible Z-scheme of the photocatalytic degradation mechanism was proposed. The heterojunction formed between Ag2ZnGeO4 and g-C3N4 could accelerate the transfer and separation of photogenerated carriers, enhancing the photocatalytic activity.